Process for recovery of nickel



April 19, 1932.

PROCESS FOR RECOVERY OF NICKEL R. c. STANLEY Filed Aug. 17, 1929 C'a/r ver/er Copper 0a, cb, P4 (fe) @raf/7 and A997770 .Ecco/poser 6b: Proa/acer lNVENTOR ATI'ORN EYJ Patented Apr. 19, i932 UNITED STATES PATENT OFFICE ROBERT IC. STANLEY, OF DONGAN HILLS, NEW YORK, ASSIGNOR TO THE INTERNA- TIONAL NICKEL COMPANY, INC., OF NEW YORK, N. Y., .A CORPORATION OF DELA- WARE' PROCESS FOR RECOVERY 0F NICKEL Application led August 17, 1929.- Serial No. 386,580.

This invention relates to an improved process for more readily and efficient-ly obtaining nickel and copper from the ores andto obtain these products directly and in readily 5 marketable forms.

More in particular the invention pertains to a novel process wherein the sequence of operations is carried out in the so-called dry way thereby eliminating the undesirable use and o handling of any material quantities of liquids.

It is an object of the present linvention toprovide an improved process for the recovery of metals from their ores by a sequence of associated metallurgical steps, all of which are carried out without the aid of any material amount of water, or in what is known as the dry Way.

It is a further object of this invention to 0 provide such an improved process for the recovery of nickel in a dry way from its ores, together with al direct recovery of copper as blister copper without resorting to the formaq tion of aqueous solutions of copper salts. i Yet anotherV object of this invention is the preliminary treatment, in the dry way, of nickel-bearing materials to obtain an impure metallic. nickel, and blister copper as a byproduct, and the subsequent treatment of the impure nickel to obtain a pure nickel.

rlfhis invention provides an improved process that is highly economical and 10W in cost and in which, by the association in a novel manner of the steps set.forth, a distinct increase in the efficiency of the complete process is obtained.

Another object of this invention is the provisionvof a process in which the percentages of nickel and copper in the mattes may vary 'a considerable amount over what has heretofore been considered as desirable limits, and still obtain very satisfactory and economical results in the production of the copper and nickel.

The foregoing and other objects and advantages of the present invention will be set forth more in detail -in the following specification, reference being 'had to the accompanying flow sheet as illustrating thepreferred sequence of steps 'in the operation of the improved process, but since other processes may be devised to accomplish the desirable results of the present invention, it is not intended to be limited to the steps herein shown except as such limitations are clearly imposed bythe appended claims.

It is Well known that there are several processes by which nickel and copper are produced from nickel-bearing materials. It is also well known that some of these processes are. carried out with greater eiiciency than others.

One of the principal processes employed in separating nickel from copper-nickel ores and mattes today is that known as the Mond process. In this process the copper-nickel matte is crushed, ground and roasted to oxide and by a complicated leaching process, a part of the copper is removed from the mixed oxides, leaving a nickel-oxide residue containing substantial amounts of copper and iron as impurities; following this, the residue is treated by the so called carbonyl process to further refine the nickel and separate the balance of the copper and other impurities. It is` an undesirable feature of the Mond process as at present practiced that a major part of the operation is carried out in the wet way involving high costs and producing copper in the form of copper sulphate, in considerable quantities which is not a l readily salable product. It is possible, of course, to recover metallic copper from this copper sulphate but only at a rather considerable cost, and at a large loss .of eiiciency. It will be seen from the description below of the process herein that it obviates the principal defects of the Mond process and very materially reduces the amount of copper sulphate produced. When there is a relatively small amount of this copper sulphate it may be sometimes sold at a satisfactory price which compensates for the manufacture and handling thereof.

Another principal process for producing nickel is that known as the Stanley process, which involves as a final operation the electrolytic reiining of the nickel, and which is described in U. S. Patent No. 1,351,877. The nickel produced by this process is in t-he' form primarily of cathode sheets, which, although cuite suitable for many types of remelting operations, do not constitute the preferable form for some operations, particularly those conducted on a small scale, such as crucible n-.elting, etc. In order to convert nickel cathode sheets into shot form suitable for small scale :melting operations, it is necessary that it be remelted, ot course at an additional cost. The nickel produced by the Stanley process has a small amount of cobalt therein. This cobalt content is not serious for most uses, but when the nickel is free of cobalt it may be more advantageous for some new and additional uses. It will be seen from the description of the process that it yields a product having certain material advantages', both in quality and in form, over those produced by the electrolytic processes above mentioned..

Another process, commonly known as the Orford process, includes the smelting of copper-nickel ores and matte with sodium or alkaline sulphides to produce a partial separation of the copper and of the nickel sulphide, following which the nickel sulphide is subjected to chloridizing,I roasting and leaching to remove the coppe.l present as an impurity in the nickel sulphide in soluble form. The impure nickel oxide residue remaining after the leaching operation is reduced and melted to metallic nickel. This process produces satisfactory metallic nickel, but it is necessary to resort to the Wet process of separating part of the copper from the nickel, Which involves increased costs, and in addition it is not possible by it to recover all of the gold, silver, platinum, cobalt, copper, and other metals which may be present, and the nickel produced is not completely free from cobalt which may be present in small amounts.

The practical advantages of the improved invention herein have been noted above, but the novel process proceeding in the dry Way gives readily marketable nickel and metallic blister copper and has given greater elficiency and economy of operation and greater quantity yield Without requiring the close attention that has heretofore been necessary. The more important advantages may be summarized as follows: Low cost of production; improved cfliciency; Si-ibstantially complete recovery of precious metals includ- ,ing platinum, palladium, gold, silver and the like; the products are produced in advantageous form; and gives improved quality and purity and particular absence of cobalt.

.Referring non1 to the flow sheet, the improved process Will be defined step by step.

A suitable nickel-bearing matte or other nickel-bea ring material is subjected to a first smelting, such as by treating with alkaline sulphides. The product of such smelting is permitted to settle so that the copper sulphide tops and the nickel sulphide bottoms nay readily separate. It will be understood that in the copper sulphide tops there Will be a small percentage of nickel sulphide, and that in the nickel sulphide bottoms there Will be a small percentage of copper sulphide. Also, this separation may be by either of tWo methods: The first allows the tops and bottoms to become solidi- .tied and later separated by breaking them apart. The second method is to produce and maintain a heated settler in Which the products of the first and/or second smeltings are introduced and then allowed to settle and are then drawn off separately in molten condition.

The copper sulphide tops pass to suitable converters Where they are blown to metallic blister copper. This production of the copper is an improvement over the Mond process in that the copp. so produced requires only the customary electrolytic refining treatment in order to put it into metallic marketable form, and is not produced in the form of crystallized copper sulphate or in an aqueous solution of copper sulphate.

There is a further economy resulting from the elimination of the copper leaching treatment in the Mond proce ss as ordinarily practiced. In the operation of leaching the copper oxide, substantial amounts of nickel 0X- ide are also dissolved in solution and are only recoverable in the form of crystallized nickel sulphate. This results in a net loss of' metallic nickel from the process and in the production of relatively less valuable product in its place.

The nickel sulphite bottoms are usually submitted to another smeltin g step, and the products thereof are permitted to separate as described above. The copper sulphide tops of the second smelting are usually passed back to the first smelting in order to obtain a purer copper and to be able to introduce more sulphides into the first smelting step, and also to thereby accomplish another economy Whenever the sodium sulphide flux is first/added to the process by being introduced into the second smelting step.

The nickel sulphide bottoms of th@ first or second smelting are crushed and ground, and leached, if desired. The leaching which is usually a Water leaching, acts to remove only the sodium or alkali sulphides wheneve i* is desired to remove these sulphides. The leaching may also remove other soluble impurities. The small amount of Water employed during the leaching process is rot sufficient to Warrant the use of the term liquid as generally used in processes of producing nickel, for the reason that none of the metal goes into solution from which it must later be recovered.

The thus produced nickel sulphide or con pound loached or not is roasted to yield n. pure nickel oxide, the sulphur dioxide being liberated. The impure nickel oxide thus formed is then subjected at temperatures from 200 C. to 600 C. to the action of a reducing gas, such as Water gas or producer gas, preferably in a multiple hearth type furnace, hereinafter called a reducer, and is thereby reduced to an impure metallic nickel possibly containing! small amounts of other metals such as goiiiV silver, copper, cobalt, and the metals of the platinum group and iron. In order to improve the reducing efiiciency ot' this gas and to put the resulting reduced oxide into the best form and condition for later volatilization operations, this reducing gas may have added to it in the proper amounts, certain other reagents includiiigv Water vapor and others.

The nickel or nickel-bearing material-s coming from the reducer furnaces are then passed to similar Jfurnaces, hereinafter called volatilizers, Where they are continuously subjected to the action of carbon monoxide gas, preierably at a temperature approximating 80- l00 C. There may be added to this carbon monoxide gas for the volatilizers certain other reagents such as SO2 or Water vapor which act to hasten the volatilization rate of nickel. The volatilizers are of the multiple hearth type furnace, which permits the solid matter therein to be continuously subjected to a gaseous atmosphere. At the indicated teinperature the carbon monoxide unites With the nickel to form the volatile compound-nickel carbonyl (NilColl), Whichpasses to decomposers Where the carbonyl is readily decomposed. The decomposers are usually vertical chambers in 'Which carbon monoxide gas carrying nickel carbonyl is brought into intimate contact with metallic nickel at a tcmperature of from 125 C. to 250 C., at Which -temperature decomposition of the carbonyl occurs, resulting in deposition of metallic nickel. This nickel is deposited on small nickel pellets or upon any surface Which is to be coated.'

The depositing of the nickel on the small nickel pellets and the removal of the larger pellets is so Well known in the art that further explanation th'ereot is not thought to be needed. The nickel pellets or nickel shot, as they may sometimes be called, are readily marketed and used in the preparation of diit'erent types of alloys requiring nickel as one of 'the constituents.

The carbon monoxide set free in the d-ecomposition step 5s returned to an earlier stage of the process and permits further economies by virtue of its high efficiency and case of manipulation.

The rcsidues from the 'volatilizers may be subjected to any special treatinerts to remove the remainder ot the copper` the gold, silver, cobalt` the metals ot the platinum group. iron, etc.

lt to be noted that although the process herein c'lfec'ls many economics in the production of nickel and copper, and gives'many advantages pertaining to the production of these materials, it is, however, particularly pointed out( that the recovery 'ot the precious metals also is accomplished with an increased etliciency andeconomiesoverotherprocessrs. By this improved process greater concentrations of precious metal 7alues are accomplished with less elt'ort or involved procedures to eli'ect concentrations than are necessary in the i'elinino; of precious metals in general. This applies to the gold, silver, platinum, palladium and other precious metals which are lnormal constituents of nickel-bearing materials.

Another feature presented by this improved process is the fact that through the use of roasted nickel sulphide bottoms an unnecessary pieduction of copper nickel sulphate salt, common to the older Mond process, is eliminated to a very large degree.

It will be appreciated that by the novel combination of steps coinprehended in the process of the present invention a new and improved result is obtained in a much more s ti-sfactory and economical manner.

The improved process of the present invention, among other things, permits the production of copper in metallic form, Whereas, at the same time, it utilizes the highly desirable lcature of the carbonyl separation method. In con-sequence the efticiency of this improved complete process is increased and the cost materially reduced. Further, the efficiency of the volatilization step of the carbonyl separation is actually increased when using the leached, roasted and reduced product ot the alkaline sulphide smelting process.

In fact, it has been found that nickel materials produced by roasting sulphides as produced in the alkaline sinelting process are more readily volatilized through th-e action of carbon monoxide than materials produced by roasting copper nickel sulphides with subsequent acid copper leaching to remove copper preliminary to the volatilization treatment.

It Will now be appreciated that there has been provided an improvcdiprocess for thc recovery of metallic nickel from copper-nickel mattes ot varying compositions which process permits the recovery of metallic copper directly during the carrying out of the necessary steps, and at the saine time avoids the disadvantage of having to carry out a substantial number of steps in a Wet Way.

It will he 'further seen that there are many advantages in this invention. Some of the more improved ones may be appropriately iiulicatcd as giving a lmaterial improvement in the general economy of production ot nickel and copper; giving greater economy -in the production ot copper by producing it iii a readily saleable form as in blister ioini; giving improvei'nents in some of the Steps of the process, some of Whichsteps have heretofore been known in a general way; giving nickel substantially cobalt free, and producing it in the desirable form of pellets; and permitting the process to be carried out in the dry way, thereby eliminating costly handling charges. Also, it is to be particularly pointed out that both the nickel and copper are produced in their most desirable forms by the single continuous rocess.

lVhen in the specification and claims l refer to carbon monoxide as the medium or agent for recovering nickel from metallic masses containing nickel and other metals, l intend to include other substances which will be equivalent to and function the same as carbon monoxide.

- lVhat is claimed is:

l. The process of recovering commercially pure metallic nickel from nickel-copper ores or mattes in a dry Way `free from Wet operations involving the dissolution of nickel and/or copper, which comprises smelting nickel-copper ores or mattes with material yielding an alkaline sulphide to convert said ore or matt-e and said material into a molten mass, permitting said molten mass to remain practically undisturbed whereby copper sulphide floats to the top of the mass and nickel sulphide contaminated with some copper sulphide settles to the bottom ot the mass, re-

moving said copper sulphide from the top i of the mass, smelting said nickel sulphide With material capable of yielding an alkaline sulphide, maintaining said nickel sulphide mass in a molten state whereby copper sul phide floats to the top of the mass and nickel sulphide settles to the bottom, removing said copper sulphide tops and returning` the :same for use in the first smelting, comminuting the nickel sulphide bottoms, roasting said coinininuted material to convert the same into an oxide, subjecting the oxide to heat in the presence ot a reducing gas including wa' treating the reduced mass containing metallic nickel with carbon monoxide to form gaseous nickel carbonyl, passing said gaseous nickel carbonyl over pellets of nickel under thermal conditions capable of decomposing said nickel carbonyl into commercially pure nickel substantially Jfree from cobalt and carbon monoxide, and recovering the carbon monoxide for .reuse in the treatment ot further amounts of the aforesaid reduced metallic mass, all of the aforesaid operations being free from Wet operations involving the dissolution of nickel and/or copper.

2. The process of recovering commercially pure metallic nickel as set forth in claim l in which material yielding sodum sulphide is used in the smelting of nickel-copper ores or mattes to convert the saine into a molten mass in which copper sulphide separates to the top thereof and nickel sulphide settles to the bottom thereof.

3. The process of recovering commercially pure nickel from nickel-copper ores or mattes in a dry Way free from Wet operations involving the dissolution of nickel and/or copper which comprises concentrating nickel sulphide from nickel-copper ores or mattes by smelting with an alkaline sulphide to effect a separation of nickel sulphide from cop er sulphide, roasting the concentrated nic rel sulphide to oxidize nickel, reducing nickel oxide to metallic nickel by a gaseous reducing agent, volatilizing said metallic nickel as nickel carbonyl and decomposing said carbonyl to produce commercially pure nickel.

In testimony whereof, I have hereunto set my hand.

ROBERT C. STANLEY. 

